Ding Lei, Li Zhenwang, Wang Xu, Shen Beibei, Xiao Liujun, Dong Gang, Yu Lu, Nandintsetseg Banzragch, Shi Zhou, Chang Jinfeng, Shao Changliang
College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China; State Key Laboratory of Efficient Utilization of Arid and Semi-arid Arable Land in Northern China, National Hulunber Grassland Ecosystem Observation and Research Station, Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing 100081, China.
Jiangsu Key Laboratory of Crop Genetics and Physiology/Jiangsu Key Laboratory of Crop Cultivation and Physiology, Agricultural College of Yangzhou University, Yangzhou 225009, China; Jiangsu Co-Innovation Center for Modern Production Technology of Grain Crops, Yangzhou University, Yangzhou 225009, China.
Sci Total Environ. 2024 Apr 10;920:170886. doi: 10.1016/j.scitotenv.2024.170886. Epub 2024 Feb 13.
The Eurasian steppe is the largest temperate grassland in the world. The grassland of the Mongolian Plateau (MP) represents an important part of the Eurasian steppe with high climatic sensitivity. Gross primary productivity (GPP) is a key indicator of the grassland's production, status and dynamic on the MP. In this study, we calibrated and evaluated the grassland-specific light use efficiency model (GRASS-LUE) against the observed GPP collected from nine eddy covariance flux sites on the MP, and compared the performance with other four GPP products (MOD17, VPM, GLASS and GOSIF). GRASS-LUE with higher R (0.91) and lower root mean square error (RMSE = 0.99 gC m day) showed a better performance compared to the four GPP products in terms of model accuracy and dynamic consistency, especially in typical and desert steppe. The parameters of the GRASS-LUE are more suitable for water-limited grassland could be the reason for its outstanding performance in typical and desert steppe. Mean grassland GPP derived from GRASS-LUE was higher in the east and lower in the west of the MP. Grassland GPP was on average 205 gC m over the MP between 2001 and 2020 with mean annual total GPP of 322 TgC yr. 30 % of the MP steppe showed a significant GPP increase. Growing season precipitation is the main factor affecting GPP of the MP steppe across regions. Anthropogenic factors (livestock density and population density) had greater effect on GPP than growing season temperature in pastoral counties in IM that take grazing as one of main industries. These findings can inform the status and trend of the productivity of MP steppe and help government and scientific research institutions to understand the drivers for spatial pattern of grassland GPP on the MP.
欧亚草原是世界上最大的温带草原。蒙古高原（MP）草原是欧亚草原的重要组成部分，对气候高度敏感。总初级生产力（GPP）是蒙古高原草原生产、状况和动态的关键指标。在本研究中，我们根据从蒙古高原9个涡度相关通量站点收集的观测GPP，对草地特定光利用效率模型（GRASS-LUE）进行了校准和评估，并将其性能与其他四种GPP产品（MOD17、VPM、GLASS和GOSIF）进行了比较。GRASS-LUE的相关系数R较高（0.91），均方根误差较低（RMSE = 0.99 gC m² day），在模型准确性和动态一致性方面，与四种GPP产品相比表现更好，尤其是在典型草原和荒漠草原。GRASS-LUE的参数更适合水分受限的草原，这可能是其在典型草原和荒漠草原表现出色的原因。源自GRASS-LUE的草原平均GPP在蒙古高原东部较高，西部较低。2001年至2020年期间，蒙古高原草原平均GPP为205 gC m²，年总GPP平均为322 TgC yr。30%的蒙古高原草原GPP显著增加。生长季降水是影响蒙古高原草原不同区域GPP的主要因素。在以放牧为主要产业之一的内蒙古牧业县，人为因素（牲畜密度和人口密度）对GPP的影响大于生长季温度。这些发现可以反映蒙古高原草原生产力的现状和趋势，有助于政府和科研机构了解蒙古高原草原GPP空间格局的驱动因素。
